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標題: | 區間窗口治療策略應用於高強度聚焦超音波肝腫瘤熱治療 Liver Tumor Thermal Therapy by Using High Intensity Focused Ultrasound with Gating Window Strategy for Respiratory Motion |
作者: | Ming-Chuan Hsu 許銘權 |
指導教授: | 林文澧(Win-Li Lin) |
關鍵字: | 超音波熱治療,區間窗口治療策略,相位陣列換能器,腫瘤呼吸移動, High Intensity Focused Ultrasound,Gating window strategy,Thermal therapy phased array transducer,Respiratory motion, |
出版年 : | 2006 |
學位: | 碩士 |
摘要: | 超音波熱治療手術為一種非侵入式的治療策略,利用超音波屬於機械波,於傳播介質當中的震動與聚焦造成組織溫度的升高。以超音波熱治療之過程,必須精確地將熱劑量送至異常組織以避免造成對正常組織的傷害。為了治療過程能夠精確地掌握,近年來,許多論文探討以核磁共振影像得知異常組織的位置,達到精確治療的目的,亦經由核磁共振的資訊引導超音波熱治療,觀察治療標定區域的溫度,掌握患部溫度上升情況,以衡量治療過程中患部的熱劑量與範圍。此外對於具移動狀態的治療區域,提供有效的資訊。
針對胸腔與腹腔的腫瘤來說,由於呼吸運動所引起的橫膈膜運動,會帶動著內臟器官做立體空間的運動。而因為治療區域的運動,會導致超音波無法準確聚焦在目標區域上。對於此項議題,我們可以利用區間窗口型加熱治療策略。若能根據影像系統擷取治療區域運動軌跡之後,對數個軌跡進行評估,得知能量分布情形,選定最適合治療的區間窗口 (Gating Windows),設計治療策略,期望利用軌跡所成之能量分布與治療硬體的配置,來達到治療的目的。 本論文中,利用馬達帶動平台運動,模擬由呼吸所引起的內臟運動軌跡,透過固定超音波換能器之平台調整至所要放置之位置,再利用兩個相同的超音波換能器對目標物作加熱。而於論文後得知於特定情況下可使治療效果達到最佳,並且經由分析軌跡資料,可掌握燒灼出現位置。利用現有設備,架構簡單的系統架構,模擬預期將得到的結果,並了解實務上將會面對遇到的問題,以利克服日後系統整合上的困難。 High Intensity Focused Ultrasound(HIFU) is a non-invasive thermal therapy surgery by using a focused ultrasound transducer to transfer the acoustic power to the tumor region. During the process of thermal therapy, it have to transfer the power precisely to avoid injuring the normal tissue. Image guidance during therapy offers the feasibility for precise thermal dose delivery to a tumor region. MR-Image offers not only the temperature field in the tissue but also some other information, such as, blood perfusion and a tumor motion…etc. Respiratory induces the diaphragm motion and the motion will result in the sequential motion of the surrounding organs and tissues. Focused ultrasound for liver tumor thermal therapy implies a risk of normal organ during the heating. In this study, we use the gating window strategy to design the treatment plan by analyzing the respiratory motion data during heating the tumor. The main system consists a servo-motor, a 256-channels phased array generator and two 80-elements ultrasound phased array. Tissue phantom on a movable plane controlled by a servo-motor was used to simulate the organ motion induced by respiration. The thermal dose distribution has been studied for the system in many conditions. The maximum temperature and maximum thermal dose location would be predicted by calculating the absorbed energy distribution. After this study, we could got a better thermal dose distribution if we rotate the phased array transducer 90 deg. in X-Y plane and the thermal lesion location could be predicted by analyzing the respiratory data. It established a simple system to know some difficulties of gating window strategy in reality and we obtained some experiment results by using this simple system. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/31993 |
全文授權: | 有償授權 |
顯示於系所單位: | 醫學工程學研究所 |
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